Sump system having timed switching of plural pumps

• US 5,449,274 A
• Filed: 03/24/1994
• Issued: 09/12/1995
• Est. Priority Date: 03/24/1994
• Status: Expired due to Term

• Current Assignee: Metropolitan Pump Company
• Original Assignee: Metropolitan Pump Company
• Inventors: Kochan, John Jr.
• Primary Examiner(s): Bertsch, Richard A.
• Assistant Examiner(s): McAndrews, Jr., Roland G.
• Application Number:
  US08/217,420
• Time in Patent Office: 537 Days
• Field of Search: 417/2, 417/7, 417/8, 417/12, 417/36, 417/40, 417/41
• US Class Current: 417/8
• CPC Class Codes: F04D 15/0218 the condition being a liquid level or a lack of liquid supply
• CPC Class Codes: F04D 15/029 for pumps operating in parallel

Abstract

An electronic pump selector system uses a programmable processor to select one of a plurality of pumps to be energized in response to an appropriate feedback signal from the selected pump. A current limited feedback circuit is incorporated which provides a varying voltage in response to a level switch associated with a selected pump indicating a high fluid level. In response to the voltage feedback signal, the selected pump is energized for a predetermined period of time. Subsequently, another pump is selected. The next selected pump is energized also for a predetermined period of time in response to a varying voltage feedback signal therefrom. The next pump is then selected and the sequence continued.

Claims

1. A pump selector usable with at least first and second pumps, each of which includes a level switch with first and second states, the selector comprising:

a first circuit for supplying a first monitoring signal associated with the first pump;

a second circuit for supplying a second monitoring signal associated with the second pump;

circuitry, coupled to said first and second circuits, for detecting a monitoring signal variation responsive to the level switch of at least one of the pumps changing state; and

pump selector circuitry coupled to said detecting circuitry, for enabling one and then the other of the pumps to be energized wherein the enabled pump is energized for a predetermined, fixed, time interval after the switch of that pump has changed state.

2. A selector as in claim 1 wherein said pump selector circuitry includes a programmed processor.

3. A selector as in claim 1 wherein said detecting circuitry includes current limiting circuitry for detecting a voltage drop responsive to a pump switch changing state.

4. A selector as in claim 1 which includes circuitry for energizing both pumps in response to a predetermined condition.

5. A selector as in claim 1 wherein said selector circuitry includes a timer for establishing a pump energizing time interval.

6. A selector as in claim 1 wherein said first and second supplying circuits include at least one element for supplying a current limited AC feedback signal.

7. A method of alternately energizing first and second pumps wherein a first ambient condition detecting switch is associated with the first pump and a second ambient condition detecting switch is associated with the second pump, the method comprising:

providing a preset time interval during which a pump is to be energized;

selecting a pump to be energized;

providing first and second current limited signals respectively to the first and second switches;

establishing first and second indicator voltages associated respectively with the first and second current limited signals;

detecting variations in the first and second indicator voltages responsive respectively to the first and second switches;

energizing the selected one of the pumps for the preset time interval in response to a detected variation in at least one indicator voltage; and

selecting the other pump and repeating at least the energizing step.

8. A pump control system comprising:

a first pump with a first condition indicating switch having a first state associated with the presence of said condition and a second state associated with the absence thereof;

a second pump with a second condition indicating switch having a first state associated with the presence of said condition and a second state associated with the absence thereof and wherein first and second voltage variations are produced in response to respective of said switches changing state;

first sensing circuit, associated with said first switch and second sensing circuit associated with said second switch wherein said circuits sense a said respective voltage variation as said respective switch changes state; and

a control circuit, coupled to said sensing circuits and to said pumps, for energizing one or the other of said pumps for a predetermined time interval which is independent of any associated fluid level in response to said voltage variations.

9. A control system as in claim 8 wherein said control circuit includes alternator circuitry for alternately energizing one and then the other of said pumps.

10. A control system as in claim 8 wherein said sensing circuits each include at least one resistive element for providing a current limited AC feedback signal to said control circuit.

11. A control system as in claim 10 wherein said feedback signal is an AC signal.

12. A pump control system comprising:

a first pump with a first condition indicating switch having a first state associated with the presence of said condition and a second state associated with the absence thereof;

a second pump with a second condition indicating switch having a first state associated with the presence of said condition and a second state associated with the absence thereof and wherein first and second voltage variations are produced in response to respective of said switches changing state;

first sensing circuit, associated with said first switch and second sensing circuit associated with said second switch wherein said circuits sense a said respective voltage variation as said respective switch changes state; and

a control circuit, coupled to said sensing circuits and to said pumps, for energizing one or the other of said pumps, for a preset time interval which is independent of any associated fluid level, in response to said voltage variations; and

wherein said control circuit includes a timer for establishing said preset time interval for energizing at least one of said pumps.